Adding unlock-like slider control for alarm dismiss/snooze.

- Ported GlowPadView and helper classes over to clock app.  Framework version
  relies on a couple hidden api's so there are minor changes to the code.
- Added necessary drawables to support slider.
- Updated proguard flags so that introspected animation methods are not
  stripped from slider widget.
- Changed lock screen view to be consistent with normal activity since existing
  landscape width is not wide enough to hold new layout. Removed the need for
  AlarmAlert. Using only AlarmAlertFullScreen now.

Change-Id: I65be41b889446ae7232488bfc2809bd2add93f6f